Field of the Invention
The present invention relates to a drive controlling apparatus for a rotary window cleaner used for an automobile and other vehicles, including a railroad car, a ship, an airplane, and the like.
A rotary window cleaner is used to clean rainwater from a front window by rotating a wiper, and is known from U.S. Pat. Nos. 4,701,972 and 5,210,900.
A drive controlling apparatus for a rotary window cleaner described in the U.S. Pat. No. 4,701,972 comprises an elevating motor for simultaneously moving up and down two wipers, which are provided on a front window so as to be close to each other, to a housing position and a start position, a drive motor for simultaneously rotating the two wipers in opposed directions at the start position, and a rotation delay setting member mounted to one junction shaft for transmitting rotation of the drive motor to the two wipers in order to prevent the two wipers from interfering with each other during rotation, thereby forming a lag angle between the two wipers to rotate them.
The drive controlling apparatus for the rotary window cleaner disclosed in the above-mentioned U.S. Patent just performs a low-speed operation and a high-speed operation but an intermittent operation can not be effected. Further, since the rotation delay setting member consists of a male member and a female member fitted to each other and a gap formed between the male member and the female member causes other wiper to be rotated late after one wiper is rotated, the operation is uncertain and an accurate lag angle cannot be formed between the two wipers, resulting in such a problem as that the two wipers interfere with each other in the high-speed rotation.
A drive controlling apparatus for a rotary window cleaner described in the U.S. Pat. No. 5,210,900 comprises an elevating motor for simultaneously moving up and down two wipers, which are provided on a front window so as to be close to each other, to a housing position and a start position, and respective drive motors for individually driving the two wipers, and a limit switch arranged for activating other drive motor after one drive motor is activated, whereby a lag angle is formed between the two wipers to rotate them in the opposed directions. However the lag angle between the two wipers is eliminated thereafter, when the two drive motors reach a certain rotational velocity. The drive controlling apparatus of this patent is adapted to connect rotating shafts of the two drive motors by a joint mechanism before the two drive motors reach the certain rotational velocity in order to prevent that the lag angle between the two wipers is eliminated and the two wipers are interfered with each other, and therefore, the two drive motors are driven by the same drive source, thereby rotating the two wipers whilst maintaining the lag angle.
The control apparatus for the rotary window cleaner disclosed in the above-mentioned U.S. Patent just performs the low-speed operation and the high-speed operation but it can not perform the intermittent drive. Further, since the joint mechanism is provided with the mechanical activating means to connect or disconnect the rotary shafts of the two drive motors with each other, the joint mechanism cannot accomplish the accurate and secure operation, and the mechanical activating means of the joint mechanism would be easily damaged owing to the shocks, because of the rotary shafts being connected with each other during rotation of the two drive motors, thus resulting in such a problem as that the two drive motors can not be accurately controlled.